1. Field of the Invention
The inventions disclosed herein relate generally to bow thrusters for marine vessels, and more particularly to novel methods and apparatus for incorporating bow thruster tunnels, motors and related equipment into boat hulls during the manufacturing process. The instant inventions eliminate the need and use of conventional glass tubes for such a process and the undesirable modifications to standard hulls through drilling and cutting of hull, as well as provide superior structural support for the thruster electrical and mechanical components.
2. Description of Related Art
Typical bow thruster installations require relatively large holes to be drilled through the hull, after the hulls original manufacture, and thereafter fiberglass tubes to be glassed in and finished to commercial standards. Such a process interferes with the structural integrity of the vessel, is inefficient, costly and time consuming. Additionally, this process can interfere with proprietary technology and methods for manufacturing boat hulls, such as that disclosed in Applicants' U.S. Pat. No. 6,726,865, Entitled COMPOSITE MATERIAL FOR VEHICLE HULLS AND HULL MOLDING PROCESS. Drilling large holes to create hull tunnels, for example 8 inches or larger, through the hull, laminates, structural components and layers would compromise the patented foam core. There is significant labor associated with the glass work and finish work associated with this type of conventional hull modification and thruster installation. It is very incompatible and unfriendly to the manufacturing environment due to the various multiple skill sets that need to be involved in the installation process to compensate for the separate requirements for subsequent modification of the hulls. These include the necessity for finishers, laminators, and experienced detail personnel for trim work, grinding procedures and the like. Eliminating the use and necessity for separate glass tunnels to be placed within a hull to receive power thrusters, and the concomitant relatively complex procedures and finishing work required, are key features of the instant inventions.
An example of a conventional bow thruster found in the prior art is U.S. Pat. No. 6,009,822 issued to Aron on Jan. 4, 2000, entitled “Bow or Stern Thruster”. The '822 patent discloses a steering device for large commercial vessels. A multi-component gearbox houses a vertical shaft which drives two horizontal shafts for props, and a pair of propellers are disposed in a cylindrical pipe defining a tunnel placed transversely across either the bow or stern of the vessel. The pipe may be made of any corrosion resistant material. The diameter of the tunnel may vary.
A further example is shown in U.S. Pat. No. 3,515,088 issued to Thulin on Jun. 2, 1970, entitled “Bow Thruster”. This patent teaches a thruster having a bulb with a partially spherical front end and an essentially cylindrical body portion merging into the ship's hull. There are two openings provided in the side walls of the cylindrical portion located diametrically opposite to each other. In the bulb proper, a tunnel structure enclosing a propeller is located. The tunnel structure is pivotably supported in the bulb and in the bulkhead and swings about a horizontal axis.
European Patent Application Publication No. 0,328,499 A1 issued to Pichl discloses a Propulsion Device for Steering a Boat, and Method of Producing a Hull, in which a hull is produced with a recess toward the bottom of the keel. The recess receives a gear/flywheel type motor, propeller aggregate assembly, the assembly being housed within a separate tunnel and cover unit of custom “V” shaped design to receive the propellers and provide flow chambers. The tunnel has an internal housing which accepts the propeller assembly, and transitions to the flow tunnels. This is a convoluted mechanical and structural design and method of manufacture, and impractical by current standards.
The prior art generally relates to conventional thrusters which use fiberglass tube inserts which are secured within cylindrical cavities drilled through the boat hulls. The tubes provide the water channels for flow when the thrusters are activated and switched on. The hulls are manufactured using a multitude of multi-layer composites, laminates and structural components of various materials and cores, as well as bow thruster designs per se.
Applicants' inventions herein eliminate the use and necessity of invading the integrity of the hull, use of separate glass tunnel, cylindrical or pipe inserts, and substantial labor and finishing work required by current and common techniques in the marine industry.